IRC 2021 Mid stair landing

[Marker707]

I'm designing a 4'-0" wide residential circular/winding stair way. (See link) My vertical rise between floors is 13'-2", well over the 11'-7 acceptable height in section R311.7.3. My first thought is, okay I'll add a landing halfway up the stairs. My question is, how wide does the landing need to be? Section R311.7.6 Landings for stairways says in part, "The width perpendicular to the direction of travel shall be not less than the width of the flight served. For landings of shapes other than square or rectangular, the depth at the walk line and the total area shall be not less than that of a quarter circle with a radius equal to the required landing width." Per R311.7.4 Walkline. The walkline shall be located 12 inches from the inside of the turn.

Am I to assume that at the walkline the depth of the landing should be 4'-0" since my stair width is 4'-0"?

 

[fatboy]

Ignoring the greek that is in the section relative to this, I would say yes, 4' depth at the walkline. I don't have a commentary handy to see if it spells it out a little more simply.

 

[tbz]

I'm designing a 4'-0" wide residential circular/winding stair way. (See link) My vertical rise between floors is 13'-2", well over the 11'-7 acceptable height in section R311.7.3. My first thought is, okay I'll add a landing halfway up the stairs. My question is, how wide does the landing need to be? Section R311.7.6 Landings for stairways says in part, "The width perpendicular to the direction of travel shall be not less than the width of the flight served. For landings of shapes other than square or rectangular, the depth at the walk line and the total area shall be not less than that of a quarter circle with a radius equal to the required landing width." Per R311.7.4 Walkline. The walkline shall be located 12 inches from the inside of the turn.

Am I to assume that at the walkline the depth of the landing should be 4'-0" since my stair width is 4'-0"?

The width of the landing stays the same or larger than the stairs served. Thus, per your sketch all 3 parts are the same width, thus good.

The wording is more for lets say you have a straight flight going up to a mid-landing that is 5ft wide, at the mid-landing you would make a 90 degree turn to another flight that is only 42" wide. Thus your mid landing would be a minimum of 60" by 42".

Simply landings must be a minimum the same width for the flight they serve, thus mid-landings serve to masters, hence the upper and lower flight.

 

[tbz]

by the way welcome to the forum...

 

[Paul Sweet]

I believe the code is written around a 90 degree change in direction. I'd consider this similar to a straight run because there is only a slight change in direction, so a 36" landing should suffice.

 

[bill1952]

Most helical stairs I've seen (a lot on legitimate stages) if they have a landing, it's a quarter circle. Most of these are 64 to 72" in diameter (is that 30 to 34" wide with typical 3 1/2" center post?) I believe at least one of the codes (LSC?) deleted the landing requirement in some conditions. You talk to regular users - stage technicians in my case - and they hate the landings and hate it forces higher risers to get head clearance. I'm sure residential are different.